Carbon dioxide is a non-polar molecule based on its dot structure. It's a linear molecule with polar bonds between the central carbon and the two oxygen atoms. The dipoles cancel out because they act in opposite directions. Carbon dioxide therefore has no dipole-dipole interations, which is why it's non-polar. The only intermolecular forces between molecules of carbon dioxide molecules are London dispersion forces, or LDFs. LDFs are caused by temporary dipoles that arise when electrons that are randomly moving around temporarily end up more on one side of the molecue. One end of the molecule will briefly be negative and the other end positive. This can induce temporary postive and negative charges on nearby molecules, and oppositely charged ends of two different molecules will be attracted to each other.
LDFs are the weakest of the intermolecular attractions. They depend on the size of the electron cloud of a molecule, as a bigger electron cloud is more polarizable. Carbon dioxide's relatively weak intermolecular attractions explain why it exists as a gas under normal atmospheric conditions.
The above describes intermolecular forces, which are those between molecules. Intramolecular forces are bonds between atoms in a molecule. Carbon dioxide has a central carbon atom that is double bonded to each of two oxygen atoms. Each double bond is four shared electrons. The bonds are polar covalent.